In the Global System for Mobile Communication (GSM), the short message service (SMS) allows mobile stations (MS) and hosts to send and receive short text and other messages. The messages are routed via a short message service centre (SMSC) which provides a complex store and forward function.
The functionality of the SMSC is outside the scope of the GSM standards and as a result no standardised interfaces have been developed for the bulk transmission and reception of SMS messages by an SMSC from a fixed network interface. In the absence of a prevailing standard, developers have devised their own proprietary protocols which have not necessarily been based on any existing standards and are therefore largely incompatible with one another.
The protocols currently used are as follows: SMPP (Short message peer-to-peer) is the most common protocol and the only non-proprietary one in wide use; EMI/UCP (External Machine Interface/Universal Computer Protocol) is a proprietary protocol developed by LogicaCMG; CIMD (Computer Interface to Message Distribution) is a proprietary protocol developed by Nokia for its own SMSC product; and OIS (Open Interface Specification) is a proprietary protocol developed by SchlumbergerSema.
Although the store and forward nature of the SMS service has advantages, the storage facilities required have a significant cost. Consequently SMSCs are relatively expensive pieces of equipment.
To address this problem, SMS router elements have been developed that enable SMS messages to be directed in the first instance to an SMS router which attempts delivery directly without passing through a store and forward function. If delivery fails then the messages are directed to an SMSC which provides a store and forward function for repeated attempted delivery of the messages. Such SMS routers are relatively inexpensive items compared to the cost of an SMSC and serve to relieve the SMSC from having to process the portion of the total traffic that can be delivered directly. Experience shows that with currently deployed networks 70%-80% of the SMS message deliveries may succeed on the first attempt. The capacity of the SMSC can therefore be lowered considerably using such devices.
SMS routers are currently available from a number of manufacturers, such as the Direct Delivery Message Router product available from CMGLogica, for instance.
However in present arrangements each node (SMS router and SMSC) needs to provide SS7 connectivity for delivery of the messages and the SMSC needs to implement and support the particular transmission protocol used by the SMS router. In practice, this means that a commercially viable SMS router product may need to implement several protocols to enable it to be used with a range of SMSCs from different manufacturers.
Furthermore, since the same bulk transmission protocol is used by the SMS router to trigger the store and forward procedure in the SMSC, and due to the fact that this protocol is in general asymmetric, the SMS router needs to implement both sides of the protocol.
This invention is directed to providing a cost-effective alternative architecture that can allow operators to avoid, or at least reduce, the use of proprietary interfaces.